Since the first Earth Day in 1970, the United States and nations around the world have made significant progress in protecting the environment.
However, there is much work to be done, and new challenges have emerged. In this timeline, we examine the progress—and the setbacks—over the past 50 years.
1970: First Earth Day
On April 22, an estimated 20 million people march in U.S. streets to call attention to the urgent need for environmental protections.
1970: “Environmental Magna Carta”
The National Environmental Policy Act takes effect in the U.S. It requires environmental impact assessments for federally permitted projects such as roads and dams.
1972: Cleaning up rivers
The Clean Water Act regulates pollution and leads to major cleanups in U.S. rivers, streams, lakes, wetlands, and coastal areas. Some even become fishable and swimmable again.
1972: U.S. bans notorious pesticide
Silent Spring had called for it; the new EPA does it: DDT is declared to be dangerous to wildlife, the environment, and potentially humans.
1972: Defending marine mammals
The Marine Mammal Protection Act shields declining populations—whales, dolphins, seals, and manatees—from hunting and harassment in U.S. waters. Their numbers begin a decades-long recovery.
1973: Saving species
The Endangered Species Act limits encroachment on the habitat of listed animals and plants. It prevents extinctions—but is attacked for infringing on property rights.
1976: Chemical plant accident in Seveso, Italy
Toxic vapors expose thousands of people to some of the highest dioxin levels ever recorded.
1978: Love Canal furor
Buried toxic chemicals sicken hundreds of residents in the community of Love Canal, near Niagara Falls, New York, calling attention to the dangers of industrial waste.
1979: Three Mile Island
A partial meltdown at a Pennsylvania nuclear power plant kills no one—but sours many Americans on nukes.
1980: Alaska wildlands protected
The Alaska National Interest Lands Conservation Act sets aside more than 100 million acres of wilderness in national parks, preserves, and refuges.
1980: Superfund program launched
The fund enables the U.S. Environmental Protection Agency to clean up hazardous waste sites. Polluters must perform the cleanup or pay for it.
1985: Discovery of the ozone hole
Scientists detect severe depletion (red) of the protective ozone layer above Antarctica. The culprits: chlorofluorocarbons and other chemicals.
1986: Chernobyl nuclear accident
A nuclear reactor explodes at the Chernobyl power plant in the Soviet Union. The blast and radiation kill 30 and force the evacuation of nearly 1,100 square miles—raising more doubts about nuclear power.
1987: Rescuing condors
The last 27 California condors are taken into captivity for breeding. A long recovery begins; today more than 200 live in the wild once again.
1987: Montreal protocol
World leaders agree to phase out ozone-depleting substances just a few years after the ozone hole is found. All nations ratify the treaty.
1988: Greenhouse effect detected
NASA climatologist James Hansen tells the U.S. Congress that carbon dioxide and other heat-trapping gases released by the burning of fossil fuels are already warming the planet.
1989: “Exxon Valdez”
The supertanker spills 11 million gallons of crude oil into Prince William Sound, Alaska.
1990: Ban on international trade in elephant ivory
It briefly slows poaching of African elephants. By 2016 Kenya is burning ivory to deter poaching.
1990: First IPCC projection
The UN’s Intergovernmental Panel on Climate Change issues its initial global warming report. Over the next quarter century, its forecasts mostly come true.
1990: Fighting acid rain
Amendments to the U.S. Clean Air Act help reduce acid rain and ozone depletion, require cleaner gasoline, and target toxic emissions and urban air pollution.
1991: Bringing ferrets back
Black-footed ferrets, once extinct in the wild, are reintroduced to the American West by U.S. Fish and Wildlife Service scientists after a captive-breeding program. They remain endangered.
1991: Kuwait oil fires
As the Persian Gulf War winds down, Iraq sets more than 600 Kuwaiti oil wells on fire. Some 1.5 billion barrels of oil are burned or spilled.
1995: Amazon forest loss
The deforestation rate rises dramatically, mostly to create cattle pasture, presaging a surge in Brazilian beef exports. Beef becomes a prime driver of rainforest destruction.
1995: Wolves return to Yellowstone
Reintroduced to the national park, gray wolves help rebalance an ecosystem suffering from an overpopulation of elk.
1995: Bald eagle recovery
The American national bird is reclassified from endangered to merely threatened. Later it is delisted completely—one of about 90 animal and plant species so far to reach that goal.
1996: Leaded gas ban in U.S.
It caps a long phaseout that caused blood lead levels to plummet. Most of Europe follows in 2000.
1997: Amphibian apocalypse
Scientists confirm that the skin-eating chytrid fungus spread by humans has been killing hundreds of varieties of frogs and salamanders. Ninety species have gone extinct to date, making it one of the most destructive known pathogens.
1997: Kyoto Protocol
To address climate change, 37 nations and the European Community pledge to cut CO2 emissions. The U.S. later fails to ratify the treaty.
1999: Golden rice
Rice is genetically engineered with vitamin A to boost nutrition in the diets of Africans and Asians.
2000: The hybrid revolution
Toyota’s Prius, the first mass-produced car with both a gasoline engine and an electric motor, arrives in the U.S. and becomes an icon of fuel efficiency.
2002: California goes solar
The state commits to getting 20 percent of its electricity from renewables by 2017. It exceeds the target—and raises it to 100 percent by 2045.
2002: Larsen B ice shelf collapses
A NASA satellite documents the breakup in a month of a 1,250-square-mile ice shelf floating off the rapidly warming Antarctic Peninsula.
2005: Hurricane Katrina
America’s costliest storm kills 1,833 people and floods 80 percent of New Orleans.
2006: Al Gore’s movie
An Inconvenient Truth helps raise public awareness about the threat of climate change and wins an Academy Award for best documentary feature. But the moment passes without significant progress in addressing the threat.
2006: Toxic waste in Côte d’Ivoire
Waste containing hydrogen sulphide and other chemicals is dumped near the port city of Abidjan. It kills 15 and sickens 100,000.
2006: China rising
With soaring coal use fueling a booming economy, China passes the U.S. to become the largest emitter of CO2. Its per capita emissions remain far lower.
2006: Shark finning
Scientists calculate that 26 million to 73 million sharks are killed annually for their fins. The shocking numbers raise alarm about shark populations.
2006: Honeybee colonies collapse
Beekeepers begin reporting the mysterious disappearance of worker bees, which is leading to the collapse of many colonies.
2006: White-nose syndrome
A fungus starts killing millions of American bats of several species, including endangered little brown bats.
2008: Electric cars get cool
Tesla Motors, founded in 2003, releases its first car, the completely electric two-door Roadster. In company tests, the sports car travels 245 miles on a single charge, an unprecedented range for a mass-produced electric car.
2008: Global seed bank
The Svalbard Global Seed Vault opens deep inside an Arctic mountain. Operated by Norway, it can store the frozen seeds of up to 4.5 million crops as an insurance policy for future generations.
2010: Deepwater Horizon oil spill
An oil rig explosion kills 11 workers and spews more than 130 million gallons of oil into the Gulf of Mexico, the largest spill in U.S. history.
2011: Fukushima disaster
An earthquake and a tsunami trigger the partial meltdown of three reactors at a Japanese power plant and massive discharges of radioactive material into the air and sea.
2012: Hurricane Sandy
New York floods; damages reach $73 billion.
2012: Arctic sea ice extent
It shrinks in September to a record minimum, about two Alaska-areas less than average.
2015: Paris climate agreement
Leaders of 195 nations agree to cap global warming at two degrees Celsius. Many countries later announce emissions cuts—though not enough to meet the two-degree goal. President Donald Trump announces that the U.S. will withdraw.
2016: Larsen C ice shelf cracks
After the Larsen B collapse in 2002, the next massive ice shelf on the Antarctic Peninsula begins to crack—just as expected from climate change.
2016: Mammal extinction
It’s the first caused by climate change: the Bramble Cay melomys, an Australian rodent.
2017: U.K. coal decline
For the first time since the 1880s, the home of the industrial revolution goes a day without making electricity from coal. The government aims to shut all coal plants by 2025.
2019: Meatless burgers
...hit the mainstream.
2019: Amazon rainforest wildfires
Fires linked to deforestation blanket much of Brazil in smoke, stoking fears that parts of the rainforest could turn to dry savanna.
2019: Australian wildfires
They burn an area larger than Iceland, killing up to a billion animals.